Electrical plug locking device



Jan. 1970 c. J. ROBACZEWSKI ,489,989

ELECTRICAL PLUG LOCKING DEVICE 2 Sheets-Sheet 1 Filed April 4, 1968 @157 wm uwz z z Jan. 13, 1970 c. J. ROBACZEWSKI ELECTRICAL PLUG LOCKING DEVICE 2 Sheets-Sheet 2 Filed April 4, 1968 United States Patent 3,489,989 ELECTRICAL PLUG LOCKING DEVICE Chester J. Robaczewski, Des Plaines, Ill. (707 Jackson Ave., Carpentersville, Ill. 60010) Filed Apr. 4, 1968, Ser. No. 718,663 Int. Cl. H011' 13/54 US. Cl. 339-75 2 Claims ABSTRACT OF THE DISCLOSURE A duplex wall outlet has a traveler movable therein toward and away from the openings which receive the prongs of electrical plugs. At each end of the traveler are a pair of pins having their outstanding ends guided for movement toward and away from the prongs of the electrical plugs. The pins are movable longitudinally thereof with respect to the traveler and have springs thereabout and bearing against abutments on the pins to resiliently urge the pins toward the prongs while permitting the pins to move, with respect to the traveler, away from the prongs. Intermediate the traveler is a handle which extends forwardly of the front of the out let to enable a user to move the traveler so that at least one of the pins will enter a hole in a prong. A latch is associated with the handle so that it may be held in the position at which a pin enters a prong to thereby lock the pin in the prong and thus lock the plug associated therewith in the outlet.

Summary of the invention The present invention relates to a simple addition to a duplex electrical outlet to provide locking pins which will enter a hole in the plug prong to lock the plug in the outlet and incorporates provision for so locking the plug despite different positioning of the holes in the plug prongs.

Description of the drawings FIGURE 1 is an elevational view of a duplex electrical outlet embodying the present invention mounted in a wall;

FIGURE 2 is a section as viewed at line 22 of FIG- URE 1;

FIGURE 3 is a front view of the duplex outlet of FIGURE 1 with the cover plate and handle removed;

FIGURE 4 is a rear view of the outlet of FIGURE 3 with the protective cover removed and a portion broken away;

FIGURE 5 is an enlarged perspective view of one end of the traveler and the locking pins thereon as employed in the present invention;

FIGURE 6 is a view similar to FIGURE 4 but with portions broken away and showing the traveler and pins removed therefrom;

FIGURE 7 is a view at line 77 of FIGURE 6;

FIGURE 8 is a view at line 88 of FIGURE 6;

FIGURE 9 is a section as seen at line 99 of FIG- URE 2;

FIGURE 10 is a perspective View of the rear protective cover; and

FIGURE 11 is an enlarged perspective view of one of the electrical contacts employed in the illustrated embodiment.

Description of specific embodiment Although the following disclosure offered for public dissemination in return for the grant of a patent is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements.

The illustrated embodiment is intended to be mounted in a wall 10 or the like. The usual practice, particularly in view of the electrical codes, is to mount the outlet in an outlet box 11 which is secured in place as by means of fastening the box to a stud 12 by fasteners such as nails 13. The illustrated embodiment comprises a body or holder 15 formed of an insulating material. Normally holder 15 will be made of a molded plastic. An insulating cover 16 and mounting strap 17 are affixed to body 15 by screws 18. An outer face plate 31 is provided for the outlet.

As is conventional, body 15 has a first pair of openings 20 and a second pair of openings 21. Each pair of openings are positioned to receive the prongs 22 of an electrical plug 23. It is conventional for prongs 22 to have a hole 24 (see particularly FIGURE 9) extending transversely therethrough. In some plugs this opening 24 is centered about 7 of an inch from the distal end of the prong, while in other plugs it is centered about A of an inch from the distal end of the prong.

Body 15 has a slot 26 in one side thereof. Movably mounted in slot 26 is a traveler 27. Intermediate the ends of traveler 27 is a guide 28. A rod 29 extends through guide 28 and is held therein by a clip 30 secured to the rod. In front of body 15 and of face plate 31, a handle 32 is threaded onto rod 29. Handle 32 and rod 29 form a manually operable means slidably connected to traveler 27 through guide 28 to permit the traveler to be moved toward and away from openings 20, 21 and prongs 22. Face plate 31 has an L-shaped slot 33 corresponding to an L-shaped slot 34 in body 15. Thus, after rod 29 has ben moved to the base of the L it may be moved sidewise to latch the rod in the base of the slot and thereby hold the traveler in that position. This sidewise movement is permitted by rod 29 being slidably received in guide 28 on the traveler.

At each end of the traveler 27 are a pair of pins 36 forming detent means. Pins 36 are movable longitudinally thereof with respect to traveler 27. Springs 37 encircle pins 36 and, bearing at one end against traveler 27 and at the other against abutments 38 on pins 36, urge the pins to the extended position illustrated in FIGURES 5 and 6. Pins 36 extend through openings 39 in body 15 and are guided by the body for movement longitudinall of the pins while restraining the pins against a movement transversely to the pins.

In a slot 41 at one side of body 15 is a contact member 42 having spaced contacts 43 at the ends thereof. The space between contacts 43 is to permit pins 36 to move therebetween as best seen in FIGURES 2 and 9. At the same time contacts 43 provide an electrical connection with one of prongs 22. The wire (not shown) to form an electrical connection with contact member 42 is held by a screw 44 threaded into an opening in extension 45 of the contact member 42.

At the other side of body 15 is a slot 47 to receive a contact member 48 having contacts 49 at the ends thereof to engage prongs 22 and provide an electrical connection thereto. The wire (not shown) to provide an electrical connection to contact member 48 is inserted between prongs 50 (FIG. 4) and an electrical conductive washer 51. Washer 51 is held captive by being received in slots 52 in body 15. After the wire has been inserted it is clamped against prongs 50 by the tightening of screw 53 threaded into opening 54 in body 15.

Before plug 23 is inserted into the socket handle 32 is moved out of the base of the L and the traveler 27 positioned in the retracted position illustrated in FIGURES l, 3 and 4. After the plug 23 has been inserted into the socket, handle 32 is grasped by the fingers and moved toward the plug, i.e. toward the center of body 15. If the plug 23 has the holes 24 in the prongs 22 adjacent the distal ends of the prongs the lower pin 36 will enter hole 34. The upper pin 36 is blocked by the prong 22 so that it moves outwardly as illustrated in FIGURE 9. When the hole 24 in the prong is adjacent about the middle of the prong and opposite the upper pin 36, the upper pin would enter that hole and the lower pin 36 would be pushed back out (the reverse of the positions illustrated in FIG- URE 9). In either event, the pin 36 will serve to lock the prong 22 in the socket. Since the pin cannot move outwardly because of being guided by the body 15 about opening 39, the pin 36 will resist an effort to withdraw plug 23. To maintain that locked position the handle 32 is moved downwardly along the base of the L shaped slot so as to be retained therein. This locked position will continue so long 'as handle 32 is left in that position. To release the plug 23, the handle 32 is moved upwardly in alignment with the upper part of the L shaped slot. This withdraws the pin 36 from the hole in the prong of the plug so that the plug may be removed from the socket.

I claim:

1. In an electrical socket having a pair of spaced opening extending inwardly normal to the front of an insulating holder to receive the two prongs of an electric plug having a hole transversely through at least one of the prongs between the two sides thereof, and electrical contacts in the holder to provide electrical contact with the prongs respectively, the improvement comprising:

a traveler mounted on said holder for movement toward and away from one of said sides of said one prong between a first position at which the traveler is close to said one prong and a second position at which the traveler is farther away from said one prong, said traveler having a pair of apertures therethrough, one aperture being closer to said front than the other thereof;

manual operating means connected to said traveler and extending outwardly from said front to permit the traveler to be manually moved between said positions;

latch means associated with said operating means to enable said operating means to be latched and thereby held in said first position until manually released; and

detent means on said traveler and positioned to enter said hole as said traveler is moved from the second to the first position to engage said one prong and prevent the removal of the plug from the holder, said detent means including a pin for each aperture and extending through the respective aperture and guided therein for movement longitudinally of the pin and transversely to said traveler, and spring means between portions of the pin and of the traveler and resiliently urging the pin toward said one prong;

said holder having means for guiding said prongs for said longitudinal movement and resisting movement of the prongs transversely of the prongs;

said electrical contact for said one prong being positioned and arranged to avoid interfering with the movement of the detent means.

2. In a duplex electrical socket as set forth in claim 1 having two pair of said spaced openings to each receive the prongs of a respective plug, wherein:

said traveler extends between each pair of openings;

said detent means includes pins as defined in claim 1 at each end thereof and opposite each pair of openmgs;

said traveler has a guide intermediate the end thereof and extending longitudinally thereof;

said operating means includes a rod received in said guide for movement with respect to the traveler and longitudinally of the traveler, said guide restraining said rod against movement transverse to said traveler, said rod extending outwardly to said front, and a handle on said rod forwardly of said front; and said latch means including a member fixed with respect to the holder and defining an L shaped slot through which said rod extends, said slot being positioned so that the base of the L is the portion thereof closest to said openings with the upper part of the L extending away from said openings.

References Cited UNITED STATES PATENTS 2,704,831 3/ 1955 Smith 339-91 2,801,394 7/1957 Derner et a1. 339 3,372,367 3/ 1968 Concannon 339-274 RICHARD E. MOORE, Primary Examiner JOSEPH H. MCGLYNN, Assistant Examiner 

